Frequent rainfall can lead to diseases in plum orchards. Failure to apply adequate protection can result in severe damage. Damage occurs due to premature decline of leaf mass, which prevents fruit ripening, so they lose their use value.
Unstable weather conditions with frequent precipitation and optimal temperatures affect the development of plant diseases such as bacterial blight of apple fruit, blight and grapevine powdery mildew. Such conditions with increased humidity create favorable conditions for the development of stone fruit rot.
Symptoms of the infection appear on the leaf and in the beginning they are pale yellow, round spots irregularly scattered on the leaves. Over time, the spots increase, becoming orange-yellow, and later orange-red. There can be up to 150 spots on one leaf. The spots merge when the entire leaf mass falls.
Since the pathogen is maintained in the fallen plum leaves, the basic measure of protection is the collection, burning or deeper plowing of the infected leaves. Another important measure is the chemical control of pathogens.
The first treatment should be done after the plum blossoms, because the leaves must be protected in the earliest stages of development. If there are conditions for infection during the vegetation, the plum should be protected with fungicides several times.
